For example, a solid polymer electrolyte fuel cell employs a polymer ion exchange membrane as an electrolyte membrane, and the electrolyte membrane is interposed between an anode and a cathode to form a membrane electrode assembly (MEA). The membrane electrode assembly and a pair of separators sandwiching the membrane electrode assembly make up a power generation cell. In the fuel cell of this type, in use, typically, a predetermined number of the power generation cells are stacked together to form a fuel cell stack mounted in a vehicle.
The in-vehicle fuel cell stack as described above is used as a component of an in-vehicle fuel cell system as disclosed, e.g., in Japanese Laid-Open Patent Publication No. 2003-173790 (hereinafter referred to as the conventional technique). As shown in FIG. 13, the fuel cell system includes a fuel cell stack 3 mounted in a front box 2 of a vehicle 1. The fuel cell stack 3 is formed by stacking a plurality of fuel cells 3a in a vertical direction.
In the front box 2, a radiator 4 is provided on the front side in the traveling direction, and auxiliary devices such as an ion exchanger 5a, an air filter 5b, an inter cooler 5c, and a super charger 5d are provided adjacent to the rear side of the radiator 4. Further, a main motor 6 as a traction motor is provided adjacent to the lower side of the fuel cell stack 3.